Step 1: Trace the origin of "Medical Sociology".
Step 1: The term's origin is attributed to a specific person in the late 1800s.
Step 2: Name the originator.
Step 2: Dr. Charles McIntire is credited with the first published use of "medical sociology" in 1894. Though figures like Talcott Parsons and Robert K. Merton expanded the field later, McIntire coined the term.
Step 3: Determine the correct choice.
Step 3: Historical sources identify Charles McIntire as the originator. Robert K. Merton was a later, significant contributor.